The present invention relates to a photographic film package in which the photographic film is light-tightly accommodated in a cartridge.
A 35 mm photographic roll film, which is widely used now, is accommodated in a light tight cartridge. The roll film is a long size film in which transparent holes, which are called perforations, are continuously provided on its both sides. A base end of the film is fixed on a spool shaft provided in the cartridge, and the film is wound around the shaft. A leading edge portion of the film is drawn out of the cartridge through a slit to which light tight fiber, which is commonly called teremp, is provided.
In the 35 mm photographic roll film, as widely known, there is provided a leading edge portion of the film, a half of the width of which is cut and formed into a long strip, which is commonly called a tongue. The leading edge portion is drawn out outside through the slit of the cartridge, and is engaged with a winding shaft of a camera.
An area of the leading edge portion of the 35 mm photographic roll film which is put on the market now is about 2023 mm.sup.2.
A film package has been disclosed in Japanese Patent Publication Open to Public Inspection No. 306,844/1989, in which: the leading edge portion of the film is not kept under the condition that it has been drawn out from the slit of the cartridge as seen in the 35 mm photographic roll film which is put on the market now; all the film is accommodated in the cartridge; and the leading edge portion of the film is pushed out from the slit of the cartridge when a shaft of the cartridge is rotated.
Further, various kinds of proposals are widely known with respect to methods of use of the film, in which the film is used not only for image photographing but also for a recording medium in which many kinds of photographing information is optically or magnetically recorded. However, all these proposals are concerning to the method in which areas not affecting a frame image, such as both end portions of the film, are used. Recently, in contrast to this, a method is proposed in PCT Patent Application W090/04205 or the like, in which: transparent, organic magnetic material is coated on a film base; and a large capacity of various kinds of information concerning the image information such as the photographic information are recorded in the film in addition to the photographic image information.
When the 35 mm roll film which is put on the market now is loaded in a camera, it is necessary for a user to stretch a curled leading edge portion of the film. It is very troublesome, and inferior film winding caused by erroneous film loading occurs.
When a film package, in which all the film is accommodated in the cartridge, is used, the foregoing erroneous film loading can be protected. However, the structure of the cartridge becomes complicated. Further, when the cartridge is not accurately produced, film thrusting is not conducted smoothly by rotation of the spool shaft, so that film winding may jam. Further, since the leading edge portion of the film does not appear outside the cartridge, it can not be judged whether the film has been used or the film is not used, by the leading edge portion of the film. Accordingly, it is necessary to provide a special means for the foregoing judgement, which is disadvantageous.
On the other hand, when the entire surface or a portion of the film base is coated with magnetic material, for example, transparent magnetic material, the film is extremely curled in its longitudinal direction. In the case of the film cassette in which the leading edge portion of the film is protruded from the slit of the cartridge, the leading edge portion of the film is excessively curled in its drawn-out direction (the longitudinal direction of the film), so that film loading into the camera is difficult, which is disadvantageous. Further, the film is excessively curled also in the lateral direction, which is also disadvantageous.